Expand both equations:
3x-3-14y-6=14 and 20x+15+12y+3=66.
Now simplify:
(1) 3x-14y=23 and 20x+12y=48⇒(2) 5x+3y=12.
Eliminate a variable:
5*(1)-3*(2): 15x-70y-(15x+9y)=5*23-3*12=115-36=79; -79y=79, y=-1.
Substitute y=-1 in 5x+3y=12: 5x-3=12, 5x=15, x=3.
CHECK: Original equations: 3(2)-2(-4)=6+8=14 Correct! 5(15)+3(-3)=75-9=66 Correct!